将双精度值舍入为小数点后2位 [英] Round double value to 2 decimal places

问题描述

我有一个双精度值为22.368511
我想舍入到2个小数位。即它应该返回22.37

I have a double value as 22.368511 I want to round it to 2 decimal places. i.e. it should return 22.37

我该如何做？

推荐答案

在大多数语言中，格式为

As in most languages the format is

%.2f

您可以查看更多示例此处

you can see more examples here

编辑

关注在25.00的情况下的显示点

I also got this if your concerned about the display of the point in cases of 25.00

{
        NSNumberFormatter *fmt = [[NSNumberFormatter alloc] init];
        [fmt setPositiveFormat:@"0.##"];
        NSLog(@"%@", [fmt stringFromNumber:[NSNumber numberWithFloat:25.342]]);
        NSLog(@"%@", [fmt stringFromNumber:[NSNumber numberWithFloat:25.3]]);
        NSLog(@"%@", [fmt stringFromNumber:[NSNumber numberWithFloat:25.0]]);
    }

2010-08-22 15:04:10.614 a.out[6954:903] 25.34
2010-08-22 15:04:10.616 a.out[6954:903] 25.3
2010-08-22 15:04:10.617 a.out[6954:903] 25

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